<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <script>
        // 测试题1
        function A() {}
        A.prototype.n = 1
        let b = new A()
        A.prototype = { // 改变A的原型属性
            n: 2,
            m: 3
        }
        let c = new A()
        console.log(b.n, b.m, c.n, c.m); // 1  undefined  2  3
    </script>
</body>

</html>